1. Field of the Invention
The invention relates to the field of thermostats, and in particular, those activated by thermal expansion systems.
2. Description of Prior Art
Austrian Pat. No. 201,890 already discloses a thermal cut-out of this type having a cup-shaped insulating casing to which are fitted the fixed contacts. The snap switch is mounted together with the expansion member on a sheet metal cover screwed onto the insulating casing. As the snap spring does not participate in the current transmission, both the adjusting element and the expansion element can act on the snap switch without interposed insulation. As a result, the snap switch and in particular the snap spring can be optimised with respect to their mechanical switching functions, so that a construction with minimum switching hysteresis is possible. In particular, there is a possibility of mounting the snap switch exclusively in knife-edge supports, which would not otherwise be possible with higher current intensities due to the current connection to the snap spring. However, this thermal cut-out has a complicated and costly construction and assembly.